The geometry shown here is also a version of "Ni's Bump," though the bump is smaller than the one used in the subsonic and transonic examples. A supersonic flow is going from left to right across the bump. As the simulation evolves, shock waves develop at the front and rear of the bump. The front shock wave actually reflects off the upper wall, back into the domain where it crosses the rear shock wave. This effect is easiest to see in a contour plot of the mach number. The technical details are given on another page.